Wrong subtitle cut using -ss input option

Description

Summary of the bug:
When applying an -ss offset on a srt subtitle file the resulting output file is cut at the wrong line and has the wrong offset.
Using the attached eng.srt file and an -ss of 0:46:38.045 i expect the cut to happen on the 641th line with a timestamp of about 7 seconds, instead it happen on the 640th line messing up with the timecodes
How to reproduce: